Electric lamp fixture



July 7, 1931. c.' A. B. HALVORSON 1,813,738.

ELEC'IRI C LAMP FIXTURE Filed Sept. 20. 1929 Inventor: Cromwell A.B.|"1alv0rson,?

Hts Attorngg Patented July 7, 1931 unrrao STATES PATENT OFFICE OROMWELL A. B. HALVORSON, OF LYNN, MASSACHUSETTS, ASSIGNOR'TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC LAMP FIXTURE Application filed September 20, 1929.7 Serial No. 394,099.

This application is a continuation in part of my application Ser. No. 320,141, filed November 17 1928. w

The invention relates to fixtures for elec- 15 tric lamps of the type especially adapted for use in connection with street or highway lighting.

In one form of fixture of the art a casing of ceramic material is used, to the lower end of which a reflector is secured. The means for securing the reflector is sometimes in the form of screws in threaded engagement with the ceramic material, the end of which screws are thrust against the section of the reflector that projects into the casing, with the result that a' pressure is set up between the reflector and the casing sufiicient sometimes to crack the ceramic material.

It is an object of the invention to provide means such as a collar on the outside of the casing to receive the thrust of the screws which otherwise would be imparted to the ceramic material and to omit any interlocking threads between the screws and the casing thereby avoiding the difiiculty above indicated.

The following specification is a full description of the invention, reference being had to the accompanying drawings, in which Fig. 1 shows a fixture comprising the features of the invention, the figure being in section and in elevation along an axial plane. Fig. 2 shows the collar for the outside of the casing in perspective.

Referring to Fig. 1 of the drawings, the fixture comprises a casing 2 which is preferably made of ceramic material such as porcelain. This casing is provided with a skirt 3 near the middle or upper portion. Just below this skirt there are provided binding posts 4 and 5, one on either side of the casing. Within the casing is located any suitable means for supporting a light source, such as an incandescent lamp 6. In the form shown this lamp is supported by a socket 7 which latter is provided with terminals 8 and 9 threaded to receive the threaded ends of the binding posts 4 and 5 respectively, the stems of which latter project into the cavity of the casing. The lower end of the casing is formed to receive the prongs 10, preferably three in number, formed about the butt end of the reflector 1011. Instead of these prongs 10 a ring may be substituted. In either case, this part of the reflector fits into the mouth of the easing as shown in Fig. 1. Each of the prongs 10 is engaged by a screw 12, said screws pass-- ing through perforations 11 (one for each screw) in the casing, there being one such screw for each of the threaded perforations 13 in the collar 14. Before the reflector is put in place the collar 14 is put in position aboutthe lower end of the casing as shown in Fig; 1, after which the screws 12 may be advanced sufficiently to enter the perforations 11 inthe casing corresponding with the perforations 13 in the collar to prevent the collar from falling. Thereafter the reflector may be inserted in place as indicated in Fig. 1, and the screws 12 advanced to engage the prongs 10 as indicated. The prongs 10 have conical recesses which provide top sloping walls 15 with which the ends of the screws engage, and these walls are so located that the screws when tightened draw the reflector 10 upward'to clamp it tightly against the packing 16 located between the lower end of casing 2 and the shoulder 17 of the reflector. This serves to provide a water-tight and dust tight joint between the casing and the reflector.

As shown in Fig. 2, the ends of the ring 14 overlap, one of the screws 13 extending through the overlapping, ends. WVhen the screw which extends through the overlapping ends is tightened, it causes the ring to expand and distort, thus binding or looking all the screws 13 in place. This serves to fix the screws against working loose thereby avoiding the use of a separate locking means. In fastening a reflector in position, the screw 13 which passes through the over-lapping ends is tightened up last, the other screws having been previously set up the desired amount.

The perforations in theceramic material, through which the screws 12 extend are larger in diameter than the screws and are free from. threads,,thus avoiding any interlocking that would permit free longitudinal movement of the screws without the necessity of turning and prevent any stresses being set up about the mouth of the casing in a radial direction with respect to the longitudinal axis of the casing along a plane containing all of the longitudinal axes of the screws. The only stress carried by the lower portion of the container, therefore, is that due to the weight of the reflector, the screws and the collar 14 inasmuch as the stems of the screws 19. rest on the walls of the perforations llj Clearly, then, the major stresses that are set up are confined to the butt of the reflector and to the ring 14: by way of the screws, the objections heretofore indicated being obviated. The construction, furthermore, is simple, cheap and substantial andenables assembling and dismantling to'be quickly and easily performed.

While I have elected to describe my invention in connection with the specific form of means shown, I do not wish to be so limited, inasmuch as other modifications are contemplated within the scope of the claims and the spirit of the invention.

l/Vhat I claim as new and desire to secure by Letters Patent of the United States is:

1. In a lamp fixture, the combination of a casing having an open end and perforations adjacent to said open end, a reflector having a portion which projects into said open end, said portion having recesses provided with sloping walls, a ring which surrounds said end and is provided with threaded perforations, a packing between the reflector and the casing, a screw in said threaded perforations which passes loosely through said firstn'amed perforations and engages said sloping walls, whereby when the screws are tightened to fasten the reflector in position, the reflector is drawn upwards to clamp it against the packing.

2. In a lamp fixture the combination of a casing having an open end and perforations adjacent to said open end, a reflector having a portion which projects into said open end, a ring which surrounds said end in spaced relation thereto and is provided with threaded perforations, and screws in said threaded perforations which pass loosely through said first-named perforations and engage said projecting portion of the reflector, said screws when tightened serving to distort the ring to lock the screws in place.

3. In a lamp fixture, the combination of a casing having an open end and perforations adjacent to said open end, a reflector having a portion which projects into said open end, a ring which surrounds said end in spaced relation thereto and is provided with threaded perforations, said ring having over-lapping ends in which one of said threaded perforations is located, and screws in said threaded perforations which pass loosely through said first-named perforations and engage said projecting portion to clamp the reflector in position, the screw through said over-lapping ends serving to distort the ring to lock the screws in position.

4. In a lamp fixture, the combination of a casing having an open end and perforations adjacent to said open end, a reflector having a portion which projects into said open end, said portion having recesses provided with sloping walls, a ring which surrounds said end and is provided with threaded perforations, said ring having over-lapping ends, packing between the reflector and the casing, and screws in said threaded perforations which-pass loosely through said first-named perforations and engage said sloping walls, whereby when the screws are tightened to fasten the reflector in position the reflector is drawn upwards to clamp it against the packing and the ring is distorted to lock the screws in position.

In witness whereof, I have hereunto set my hand this 17th day of Sept, 1929.

CROMVVELL A. B. HALVORSON. 

